Introduction to geochemical modeling / Введение в геохимическое моделирование

The chemical evolution of geological reservoirs, such as the upper mantle, an oceanic basin, or a magma chamber, results from the competition of two opposing kinds of processes. From a parent system with uniform (or at least smoothly changing) geochemical properties, differentiation processes generate subsystems in which these properties are usually different. Among the differentiation processes, we can mention phase changes such as crystal fractionation and partial melting, mechanical sorting, and biological activity. In the opposite direction, mixing processes tend to combine systems with distinct geochemical properties into more uniform supersystems. Mixing obviously plays a fundamental role in the formation of clastic sedimentary rocks and magmas emplaced on continental crust, while being responsible on a broad scale for the rather simple chemical properties of seawater and the isotopic characteristics of the mantle sources of basalts. This chapter deals with the basic principles of mass conservation associated with mixing and differentiation processes. <...>